Formulation of the problem. At the present historical stage, the issue of European continental security is becoming especially relevant against the background of Russian aggression. This is obvious and hardly questionable. Ukraine has always played the role of a defender of Western civilization in European history. Apart from Ukraine, Poland and Lithuania have performed and continue to perform the same function. Speaking in the language of historical analogies and comparisons, it is impossible in this aspect not to mention such a large and powerful state formation as the Commonwealth. Ironically, this state also emerged against the background of Muscovy's expansion in the east. The need for common security in Central Europe has always been and remains relevant. Lithuania, Poland and Ukraine are at the forefront of Europe's sustainable development. Today it is the forefront of the entire civilized world. Therefore, the formation of the Lublin Triangle between Kyiv, Warsaw and Vilnius is a historical, political, economic, humanitarian necessity. In fact, the Lublin Triangle is a tripartite regional alliance for political, economic, cultural and social cooperation between Lithuania, Poland and Ukraine, aimed at strengthening dialogue between countries, supporting Ukraine's integration into the European Union and NATO and jointly countering Russian aggression in Ukraine. The idea of such a union belonged to Vyacheslav Chornovil and Adam Czartoryski. The economic component of this association is extremely important, as it is the basis for the formation of a system of sustainable development of the region. European aggression is contrasted with European balance and economic stability. Analysis of recent research and publications. The theme of the Lublin Triangle and the importance of this organization in the modern development of Europe is becoming increasingly important. However, this issue is still more in the political and journalistic sphere of consideration. Economic research on this topic has not yet been developed. Although some attempts are being made. Rather, the scientific issues themselves are determined, which in the future will have different areas of research. The purpose of this study is to analyze the state and prospects of the unification of Poland, Lithuania and Ukraine as a stabilizing economic factor in the security system of Europe within the framework of the Lublin Triangle. Results of the research. The analysis of this issue proves that the unification of the three states - Poland, Lithuania and Ukraine, within the Lublin Triangle has serious prospects and can act as a powerful formation in the economic security of Europe, especially in the context of Russian military expansion. Conclusions. The Lublin Triangle, as an intergovernmental union, is primarily designed to counter Russian aggression and pressure on the European Union. The role of Ukraine, Lithuania and Poland for many centuries has been to protect the European continent from Russia's imperial advance on Europe and to slow down the development of European countries. At the present time, this problem has become very acute and significant. The countries of the Lublin Triangle have a strong economic potential, are of serious trade and communication interest in the North-South, West-East directions, and are a kind of outpost in defense of Western civilization. The Lublin Triangle political union is quite capable of economically protecting Europe from the negative impact of Russia's expansion on the EU.